The present invention relates to gate valves for controlling fluid flow through a longitudinal passage. The present invention further relates to methods of controlling fluid flow through a longitudinal passage, and methods of servicing valves used to control fluid flow.
The presently described gate valve may be used in particular to shut off high pressure flows. One of the problems commonly associated with gate valves, and particularly with high pressure shut-off gate valves, is that the seals used therein are undesirably subjected to high-pressure wear as the valve gate is slid between an opened and closed position. As the valve gate slides shut, the seal associated therewith may be subject to a high-pressure jet of fluid as the flow is pinched off by the valve.
A typical prior art valve mechanism is shown in FIG. 1 of Penick et al., U.S. Pat. No. 2,229,871. In Penick, the valve member 3 includes a side seal ring 17 that is in constant contact with the valve casing 1 as the valve member slides between opened and closed positions. As the gate (valve member 3) in Penick pinches off the last bit of fluid flow through the transverse opening 16, the seal 17 is directly in the path of a very high-pressure flow that may erode the seal material. As a result, the seal 17 may fail, or at the least, the valve may require frequent maintenance.
Valve maintenance is another problem commonly associated with high-pressure shut-off gate valves. In order to service a valve such as the one shown in Penick, the complete valve mechanism may need to be disconnected from the pipes that it connects. Removal of the entire valve can be a complicated and lengthy procedure, resulting in high maintenance costs and prolonged downtime of the fluid delivery system in which the valve is imbedded.
Still another problem associated with prior art valves, such as the one shown in Penick, is the disruption of laminar flow past the valve as it moves from an opened position to a closed position. With renewed reference to FIG. 1 of Penick, as the valve member 3 is slid downward, the flow through the transverse opening 16 is slowly cut off by the upper portion of the valve member. The fluid flow through the valve becomes turbulent because the flow experiences either complete blockage from the upper portion of the valve member 3, or an oddly shaped passage formed by the combination of the semi-blocked transverse opening 16 and the lower portion of the valve casing 1. This turbulent flow may be problematic for a variety of reasons, including its contribution to the erosion of the seals subjected to the turbulent flow.
Applicant has developed a gate valve, and methods of operating and servicing the gate valve, that alleviate, at least to some extent, the above-referenced problems of the prior art. Applicant""s gate valves and methods involve the use of a valve with a frusto-conical gate and a mating seat which result in reduced seal wear, improved flow characteristics during transition of the gate, and improved valve serviceability. The tapered gate and seat provide for a unique type of seal having reduced drag on the seal when the valve is open. In accordance with Applicant""s gate valves and methods, the sealing surface of the gate may travel freely right up until it contacts the frusto-conical seat. The gate sealing surface is only in contact with the seat surface after the valve is in the fully closed position. This feature may result in longer life for the sealing surfaces.
It is therefore an object of the present invention to provide a gate valve and method of operating a gate valve that subjects the sealing surfaces of the valve to less wear than some prior art valves.
It is another object of the present invention to provide a gate valve and a method of operating a gate valve that produces a less turbulent flow through the valve as it is moved between opened and closed positions.
It is a further object of the present invention to provide a gate valve that may be more easily serviced than some prior art valves.
It is yet another object of the present invention to provide a method of servicing a gate valve.
It is still yet another object of the present invention to provide a gate valve employing a frusto-conically shaped seat and a mating frusto-conically shaped gate.
Additional objects and advantages of the invention are set forth, in part, in the description which follows and, in part, will be apparent to one of ordinary skill in the art from the description and/or from the practice of the invention.
Responsive to the foregoing challenges, Applicant has developed an innovative valve for controlling fluid flow comprising: a housing having a longitudinal passage and a substantially orthogonally oriented bore intersecting the longitudinal passage; means for sealing the orthogonally oriented bore from an ambient surrounding the housing; a sleeve disposed in the orthogonally oriented bore; a frusto-conical cavity provided in the sleeve; first and second openings extending through the sleeve and aligned with the housing longitudinal passage; a gate contained by the means for sealing and at least partially disposed in the sleeve, said gate having a frusto-conical portion and a cylindrical portion; a linear passage extending through the gate cylindrical portion, said linear passage being adapted to align with the sleeve first and second openings; and means for sliding the gate relative to the sleeve so as to seat the frusto-conical portion of the gate against the frusto-conical cavity of the sleeve.
Applicant has further developed an innovative gate valve for controlling fluid flow through a housing, comprising: a housing with an internal bore and a flow passage intersecting and oriented transversely to the internal bore; a sleeve disposed in the internal bore, said sleeve having an internal frusto-conical seat and openings aligned with the housing flow passage; a gate adapted to be at least partially disposed in the sleeve, said gate having a frusto-conical portion; and means for moving the gate frusto-conical portion into the sleeve and transversely through the fluid flow until the frusto-conical portion of the gate contacts the internal frusto-conical seat of the sleeve.
Applicant has still further developed an innovative method of operating a gate valve comprising the steps of: providing a gate valve having a gate with a frusto-conical portion and a sleeve with a frusto-conical seat; providing fluid flow through the sleeve substantially orthogonal to the orientation of the frusto-conical seat; moving the frusto-conical portion of the gate transversely through the fluid flow; and maintaining the frusto-conical portion of the gate out of contact with the frusto-conical seat until a point that fluid flow through the sleeve is shut off.
Applicant has further developed for a gate valve having: a housing with an internal bore and a flow passage oriented transversely to the internal bore; a sleeve disposed in the internal bore, said sleeve having a frusto-conical seat; a gate at least partially disposed in the sleeve, said gate having a frusto-conical portion; and a cap for sealing the sleeve and gate within the housing, an innovative method of servicing the gate valve comprising the steps of: removing the cap from the housing; removing the gate from the housing; removing the sleeve from the housing; inserting a new sleeve into the housing; inserting the gate into the housing; and connecting the cap to the housing.
Applicant has further developed an innovative gate valve for controlling fluid flow through a housing, comprising: a housing with an internal frusto-conical seat and a flow passage intersecting and oriented transversely to the internal frusto-conical seat; a gate at least partially disposed in the housing, said gate having a frusto-conical portion; and means for moving the gate frusto-conical portion transversely through the fluid flow towards the housing frusto-conical seat until the frusto-conical portion of the gate contacts the housing frusto-conical seat.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated herein by reference, and which constitute a part of this specification, illustrate certain embodiments of the invention and, together with the detailed description, serve to explain the principles of the present invention.